I use a router and have a dynamic IP and I also use dns2go, so having a router is no problem.
I also agree that IIS's ftp isn't that great and not as easy and configurable compared to warftp and serv-u. I've tried many FTP software and war and serv are my two top picks. While I do like the ton of options warftp has, I prefer serv-u because of it's on going support (I know war is not dead but it sure has been in active) and has some really nice features, also for the novice I think serv-u is easier to setup.